The present invention relates to a pneumatic brake pipe pressure regulating valve device and more particularly to such a valve device that exhausts the pressure in the brake pipe of a railroad train at a location remote from the train locomotive consistent with a brake valve regulated service reduction of brake pipe pressure at the train locomotive.
There is currently an ongoing effort underway to develop electro-pneumatic brakes for railroad freight trains. It is generally acknowledged that such electro-pneumatic brake control can enhance train operation by achieving faster brake response, more equalized car retardation, and uniform braking effort throughout a long train of cars. This implies that all of the cars or at least a majority of the cars in a train be appropriately equipped for electro-pneumatic braking, in which case direct brake cylinder pressure control is envisioned. With the exception of certain unit trains, however, it cannot be reasonably expected that any such majority of cars would be immediately implemented with the required electro-pneumatic equipment. Accordingly, indirect brake cylinder pressure control is contemplated, in which the train brake pipe pressure is controlled at one or several remote cars throughout the train to accelerate reductions of brake pipe pressure in order to obtain faster brake response.
Presently, railroad trains are required to carry an end-of-train unit on the last car, which, among other functions, may be equipped to independently and remotely initiate an emergency reduction of brake pipe pressure from the rear of the train in response to the operator activation of a special triggering device in the locomotive. This is accomplished by transmitting an emergency brake application command signal from the locomotive to the end-of-train unit via radio communication.